This invention relates in general to stock stops for use in multiple spindle lathes and in particular to an improved stock stop for positively positioning a length of bar stock within such a lathe which is quickly and easily changeable.
The multiple spindle lathe is a commonly known machine which is designed to simultaneously support a plurality of workpieces (in the form of elongated bars of stock material) and to selectively remove material therefrom. To accomplish this, the spindle lathe is provided with a plurality of workpiece supporting spindles. Typically, four, six, or eight of such spindles are mounted in a circular array on a carrier assembly. Each spindle is constructed such that the bar stock is advanced axially therethrough from a rearward end, where the bar stock is supplied to the spindle lathe, to a forward end, where one or more machine tools are located.
A conventional clamping collet is provided at the forward end of each of the spindles. When the collet is opened, the bar stock can be advanced axially through the spindle so that the leading end thereof is exposed to the machine tools for selective metal removal. A stock feeding mechanism is provided for automatically advancing the bar stock axially through each of the spindles when the collet is opened. The stock feeding mechanism moves the bar stock forwardly through the spindle until the leading end of the bar stock engages a stock stop mounted on the spindle lathe. Then, the collet closes so as to tightly grip the bar stock for engagement by the machine tools to form a finished article.
The stock stop is located on the spindle lathe such that a predetermined length of bar stock is advanced beyond the forward end of the spindle and, therefore, is exposed for engagement by the machine tools. This predetermined length is dependent upon the size and shape of the article to be formed. Obviously, it is desirable that the spindle lathe be capable of machining a number of differently sized and shaped articles. Therefore, the stock stop is generally mounted on the spindle lathe in an adjustable manner so that the relative position thereof can be varied to accommodate the manufacture of differently sized articles.
Although known stock stops are adjustable, they have been found to be rather slow and inefficient to adjust from article to article. Generally, such adjustment requires that an operator reach within the spindle lathe and re-position the stock stop on a trial and error basis until the desired length of bar stock is achieved during a stock feeding operation. This problem is particularly acute when the spindle lathe is used to manufacture low volumes of articles. In this situation, frequent, time-consuming adjustments of the stock stop are necessary. Accordingly, it would be desirable to provide an improved stock stop for a spindle lathe which is quickly and easily adjustable.